DS3-S20 Rexroth Solenoid Directional Valve 100 L/min 350 Bar

Product Overview

The DS3-S20 series direct-acting solenoid directional control valve (model DS3-S20/11N-D24K1) is a high-performance solenoid-operated directional valve manufactured to advanced European hydraulic standards. Belonging to the DS3 series with size 6 (NG6 / CETOP 03), this valve features a direct-acting subplate mounting design conforming to ISO 4401-03 (CETOP RP121H) standards. Actuated by wet armature solenoids, the control spool provides precise directional switching control for hydraulic actuators.

This product is dimensionally and functionally identical to the original Rexroth 4WE6 series and Duplomatic DS3 series valves. Per industry interchange standards, the DS3-S20 directly replaces Rexroth 4WE6 series valves with equivalent spool functions, offering true drop-in interchangeability without modifying piping systems or mounting interfaces. Every unit undergoes 100% bench testing under simulated working conditions, including rated pressure holding, directional response verification, internal leakage measurement, and solenoid response characterization, ensuring performance consistency with the original equipment.

Technical Specifications 

General Specifications

• Model: DS3-S20/11N-D24K1

• Product Series: DS3 (Size 6 / NG6 / CETOP 03)

• Spool Type: S20 (All ports closed in neutral)

• Design: Direct-acting, subplate mounting solenoid directional valve

• Ways/Positions: 4-way, 3-position

• Mounting Pattern: ISO 4401-03 / CETOP RP121H

Hydraulic Parameters

• Maximum Operating Pressure (Ports P/A/B): 350 bar (5075 psi)

• Maximum Tank Port Pressure (Port T): 160 bar (standard)

• Maximum Flow Rate: 100 L/min (DC solenoid)

• Hydraulic Fluid: Mineral-based hydraulic oil (HL / HM per ISO 6743-4)

• Viscosity Range: 10 – 400 cSt (mm²/s)

• Recommended Viscosity: 25 cSt

• Fluid Temperature Range: -20°C to +80°C

• Ambient Temperature Range: -20°C to +50°C

• Filtration: ISO 4406 20/18/15 (NAS 1638 Class 10)

Electrical Parameters

• Solenoid Type: Wet armature solenoid with interchangeable coil

• Supply Voltage: 24 VDC (D24)

• Coil Resistance: approx. 18.6 Ω @ 20°C

• Rated Current: approx. 1.29 A

• Power Consumption: approx. 31 W

• Electrical Connector: K1 (DIN 43650 standard connector)

• Protection Class: IP65 (with standard connector)

Materials & Construction

• Valve Body: High-strength cast iron with wide internal passages to minimize pressure drop

• Control Spool: Carburized steel, precision ground

• Seals: NBR (standard) / FKM (optional, for phosphate ester fluids)

• Surface Treatment: Phosphating (standard) / zinc-nickel coating (optional, 240-hour salt spray resistance)

Weight & Installation

• Weight: approx. 2.0 kg (dual solenoid version)

• Mounting: Subplate mounting, any position

• Mounting Bolts: 4 × M5 (ISO 4762, grade 12.9)

Key Technical Advantages

1. High-Strength Cast Iron Body with Optimized Flow Passages
The valve body is cast from high-strength iron with CFD-optimized internal flow passages that maximize flow area and effectively reduce pressure drop. At the rated flow of 100 L/min, the P→T pressure differential is significantly lower than comparable products, reducing system energy loss and fluid temperature rise while improving overall hydraulic system efficiency.

2. Wet Armature Solenoid with Interchangeable Coil Design
The oil-immersed (wet armature) solenoid design places the armature in hydraulic fluid, effectively reducing shifting impact noise and wear. The interchangeable coil design allows coil replacement without removing the entire valve body, significantly reducing downtime and maintenance costs. DC solenoids can also be fed with AC power supply by using connectors with a built-in rectifier bridge.

3. Precision Spool Machining with Multiple Spool Functions
The control spool is precision-ground from carburized steel, with micron-level clearance control ensuring low internal leakage and responsive shifting performance even at 350 bar operating pressure. The DS3 series offers multiple interchangeable spool functions including closed center (S20), open center (S2), A/B to tank (S3), and tandem center (S4), meeting diverse hydraulic circuit design requirements.

4. 100% Simulated Working Condition Testing and Drop-in Interchangeability
Every DS3-S20/11N-D24K1 valve undergoes 100% bench testing prior to shipment, covering 350 bar rated pressure holding, directional response time measurement, internal leakage verification, and solenoid response characterization. Mounting dimensions, port positions, electrical interfaces, and performance curves are strictly matched to the original Rexroth 4WE6 series and Duplomatic valves, enabling direct drop-in replacement without modifying piping or control programs, significantly reducing Total Cost of Ownership (TCO).

Application Areas

• Machine Tools: CNC hydraulic clamping systems, tool changer control

• Injection Molding Machines: Mold opening/closing direction control, ejector system control

• Hydraulic Presses: Main cylinder directional control, fast/slow speed switching

• Metallurgical Equipment: Continuous casting machines, rolling mill auxiliary directional control

• Construction Machinery: Mini excavators, loader auxiliary hydraulic circuits

• Marine Hydraulics: Steering gear control, deck machinery hydraulic systems

• Testing Equipment: Material testing machine hydraulic loading direction control

Expert Maintenance Tips

Installation Guidelines

1. The DS3-S20 series can be mounted in any position. Mounting surface flatness must be ≤ 0.05 mm. Use grade 12.9 M5 bolts and tighten diagonally in stages to the recommended torque value.

2. Thoroughly flush all piping circuits before installation. Ensure no welding slag, metal chips, or particulate contaminants remain. Prior to first operation, circulate the system through a 10 μm filter element for a minimum of 30 minutes. The wide internal passages provide some contamination tolerance, but fluid cleanliness should still be maintained at ISO 4406 20/18/15 or better.

3. Solenoid drain port (if equipped) must return independently to the reservoir and must not share a common return line with other high-pressure circuits to avoid back pressure causing shifting malfunction.

Routine Maintenance Procedures

1. Fluid Cleanliness Management: Maintain system fluid cleanliness at NAS 1638 Class 10 or better. Check fluid particulate contamination every 500 operating hours and replace filter elements and hydraulic fluid when contamination exceeds limits.

2. Solenoid Electrical Inspection: Periodically measure coil resistance (standard value approx. 18.6 Ω @ 20°C). Replace the coil if deviation exceeds ± 10%. Inspect the DIN 43650 connector for seal integrity and terminal tightness to maintain IP65 protection.

3. Shifting Performance Verification: Periodically check each position for smooth shifting and absence of binding. If shifting response becomes sluggish or internal leakage increases, inspect spool wear and fluid contamination levels.

4. Seal Replacement: Under normal operating conditions, replace valve seals every 3,000-5,000 operating hours. When using phosphate ester fluids (HFDR), FKM seals (code V) must be used; NBR seals are not compatible.

5. Back Pressure Management: Tank port back pressure must not exceed 160 bar (standard version). If system return back pressure is high, select the CA version (T port rated to 210 bar) or implement independent return measures.

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